noise in the turbo, car has 60,000 miles

There is a common problem with the waste gate making some clanking noise, but it's mainly there at deceleration. Unfortunately I have seen turbos going out a little over warranty when the owner kept up with the manufacturer's suggested oil change interval, which is - in my opinion - way to long to maintain correct lubrication, especially for turbo engines. I suggest Mobil1 or AmsOil and no more than 5000 miles between oil changes. The turbo runs on extremely high temperatures and just baking the oil, which brakes down pretty soon. Do you see gunk and carbon deposit when you remove the oil filler cap? Zee